CVE-2021-32764
YouTube Onebox susceptible to XSS
Discourse is an open-source discussion platform. In Discourse versions 2.7.5 and prior, parsing and rendering of YouTube Oneboxes can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. The issue is patched in stable version 2.7.6, beta version 2.8.0.beta3, and tests-passed version 2.8.0.beta3. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
YouTube Onebox susceptible to XSS
Discourse is an open-source discussion platform. In Discourse versions 2.7.5 and prior, parsing and rendering of YouTube Oneboxes can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. The issue is patched in stable version 2.7.6, beta version 2.8.0.beta3, and tests-passed version 2.8.0.beta3. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
- Record
CVE-2021-32764- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-19532
Discourse is an open-source discussion platform. In Discourse versions 2.7.5 and prior, parsing and rendering of YouTube Oneboxes can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. The issue is patched in stable version 2.7.6, beta version 2.8.0.beta3, and tests-passed version 2.8.0.beta3. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
- Record
EUVD-2021-19532- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
NVD
Discourse is an open-source discussion platform. In Discourse versions 2.7.5 and prior, parsing and rendering of YouTube Oneboxes can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. The issue is patched in stable version 2.7.6, beta version 2.8.0.beta3, and tests-passed version 2.8.0.beta3. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
- Record
CVE-2021-32764- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
Discourse is an open-source discussion platform. In Discourse versions 2.7.5 and prior, parsing and rendering of YouTube Oneboxes can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. The issue is patched in stable version 2.7.6, beta version 2.8.0.beta3, and tests-passed version 2.8.0.beta3. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
- Record
CVE-2021-32764- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-02
OSVBIT-discourse-2021-32764 No score
YouTube Onebox susceptible to XSS
Discourse is an open-source discussion platform. In Discourse versions 2.7.5 and prior, parsing and rendering of YouTube Oneboxes can be susceptible to XSS attacks. This vulnerability only affects sites which have modified or disabled Discourse's default Content Security Policy. The issue is patched in stable version 2.7.6, beta version 2.8.0.beta3, and tests-passed version 2.8.0.beta3. As a workaround, ensure that the Content Security Policy is enabled, and has not been modified in a way which would make it more vulnerable to XSS attacks.
- Record
BIT-discourse-2021-32764- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
discourseBitnami |
through 2.7.5 | None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32764 is a high vulnerability (CVSS 8.1) in Discourse, published July 15, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.55%, the 46th percentile. No source names a fixed version.